Rotating transformer structure



Dec. 17, 1968 F. M. BAILEY 3,417,219

ROTATING TRANSFORMER STRUCTURE Filed March 15, 1966 2 Sheets-Sheet 1FIG. I

INVENTOR FRANCIS M. BAILEY Dec. 17, 1968 F. M. BAILEY 3,417,219

ROTAT ING TRANSFORMER STRUCTURE Filed March 15, 1966 2 Sheets-Sheet 2FIG. 2

INVENTOR FRA NC 15 M LT-A I LL) WW6. M

United States Patent Oflice 3,417,219 Patented Dec. 17, 1968 ROTATINGTRANSFORMER STRUCTURE Francis M. Bailey, Roanoke, Va., assignor toGeneral Electric Company, a corporation of New York Filed Mar. 15, 1966,Ser. No. 534,516 2 Claims. (Cl. 219---10.61)

ABSTRACT OF THE DISCLOSURE This invention relates to a thermoelectriccontrol for a rotating metallic surface over which synthetic fibers arepassed in contact therewith during processing of such fibers.

More specifically, the invention is directed to a rotating transformerstructure in combination with a hot roll type of fiber heater wherebythe temperature of the roll surface, corresponding most accurately tothe temperature of a fiber contacting the roll, is controlled forpurposes of regulating the fiber temperature.

Many synthetic fibers, such as polypropylene and polyester, requireprocessing with heat while in filament form, the heat being required fordenier reduction, stress relief and the like. The low thermalconductivity of such fibers requires that the fibers be heated by directcontact with a heating surface such .as a metallic heated surface. Because of the delicate mechanical nature of these fibers duringprocessing it has been advantageous to make use of a heating device suchas a heated, rotating metal roller in order to reduce the frictionaldrag on such fibers.

A problem arising under the conditions enumerated above is the accuratedetermination of the roller temperature and the control thereof. Acommon solution to this problem might be the use of conventional sliprings to which a thermistor contained in the roller per se is connected.However, the temperature variations required to be controlled are ofsuch small magnitude in fiber heating equipment that the slip ringcontacts provide both unreliable and inaccurate variations so that theeffectiveness of control is unsatisfactory.

It is therefore an object of this invention to provide a roll typeheater control whereby the roll surface temperature can be determinedaccurately within the limits required in the heat treatment of syntheticfibers.

A feature of the invention is the use of a rotating transformerstructure in combination with a roll type heater for providing anaccurate reflection of the true temperature of the (heater surfacewithout the normal electrical interference encountered in the use ofslip ring devices.

The invention is set forth with particularity in the appended claims.The principles and characteristics of the invention, as well as otherobjects and advantages are revealed and discussed through the medium ofthe illustrative embodiments appearing in the specification and drawingswhich follow.

In the drawings:

FIGURE 1 is a sectional view in perspective of a roll type heateraccording to the invention.

FIGURE 2 is a simplified view of the essential structure of FIGURE 1illustrating one embodiment of a rotating transformer arrangement.

FIGURE 3 is another simplified view of the essential structure of FIGURE1 illustrating another embodiment of a rotating transformer arrangement.

With reference to FIGURE 1 a motor shaft 11 (motor not shown) having areduced diameter forming a shoulder 13 provides a means for rotating ametallic heating drum 17, the latter being provided with a hub 19slidably fitted to the shaft 11 via a threaded portion 15 to which thehub 19 is attached and held against the shoulder 13 by a nut 21. Asupport ring 23 is held in position against the hub 19 by mountingscrews 25 and 26, the ring 23 supporting a core 27 and a winding 29,which in effect comprise the core and one winding of a rotarytransformer. The core 27 is fastened to the support ring by screws 33.The leads 35 and 36 of the Winding 29 are permanently connected to athermoelectric device (thermistor) 37 located in the shell 39 of thedrum 17 over which a filament of synthetic fiber is passed for heatprocessing, either being wrapped around the drum 17 or contacting aportion of the drums surface 41.

A plate 51 is mounted in spaced relationship with the aforementioneddrum 17 structure in a manner to permit the shaft 11 to projecttherethrough, and is provided with heat shields 53 and 54 carried by asupporting ring 55, which is attached to the plate 51 by screws 57 and58. A stationary core 59, together with a stationary winding 61 ismounted within the supporting ring 55, resting against the heat shield53 and held in position by a series of washers 63 and screws 65 attachedto plate 51. The leads of the Winding 61 are brought through the heatshield 53 and the plate 51, terminating as leads 69 and 71. Thestationary core 59 and winding 61 form another component of a rotarytransformer for coacting with the aforementioned movable core 27 andwinding 29 via the air gap therebetween. A heating unit 67 is providedaround the heat shield 54 under the drum shell 39, the unit beingfastened by suitable insulating means to the plate 51 and being closelyspaced from the inside of the shell 39, the heating unit being energizedfrom an electrical power source (not shown).

The leads 69 and 71 may be connected into one arm of an alternatingcurrent bridge apparatus (not shown) so that any variations of theimpedance of the thermistor 37, transmitted via the windings 29 and 61and their respective cores, are detected by the bridge circuit forcontrolling the current applied to the heating unit 67 in any of manywell known voltage regulator arrangements (not shown). In this manner byestablishing a predetermined temperature of the drum shell 39 of thedrum 17, as measured by the thermistor 37, the temperature of thesurface 41 and fiber filaments in contact therewith can be maintainedconstant.

Although the preferred embodiment 'of the invention is illustrated inFIGURE 1, a simplified rotary transformer arrangement is shown in FIGURE2 which may be adapted to a rotating heat roll of the type previouslydescribed. In this instance an inner cylindrical core having a winding82 is spaced inside another cylindrical core 81 having a winding 83 forrotation, the leads 84 and 85 of the winding 82 being brought out an endof the core 80 and the leads of the winding 83 being brought out an endof the core 81, the cores 80 and 81 being relatively rotational.

A modified form of the structure of FIGURE 2 is shown further in FIGURE3 where an outside stationary cylindrical member 91 having layers ofsilicon steel core material 99 wound in cylindrical fashion to conformto the contour of cylinder 91 and carrying a single layer winding 95insulated from the core material 99 by a layer of insulation 111. Aninner cylindrical member 93 similarly provided with layers of siliconsteel core material 101, a winding 97 insulated from the core by a layerof insulation 113 is arranged to rotate within the cylindrical member91, the leads 103, and 107, 109 respec- 3 tively providing electricalconnections to the windings 95 and 97.

While the invention has been explained and described with the aid ofparticular embodiments thereof, it will be understood that the inventionis not limited thereby and that many modifications retaining andutilizing the spirit thereof without departing essentially therefromwill occur to those skilled in the art in applying the invention tospecific operating environments and conditions. It is thereforecontemplated by the appended claims to cover all such modifications asfall within the scope and spirit of the invention.

What is claimed is:

1. A synthetic fiber heater including a rotatable roll, stationary[heating means coacting therewith, a thermoelectric device in said rollfor determining its temperature, a winding carried by said rollconnected to said device, a magnetic core for said winding, a stationarywinding, and a magnetic core for said stationary winding, the said coresbeing spaced .apart from each other by an air gap and the said windingsbeing inductively coupled via said cores whereby a representation 'ofthe temperature of said roll is provided in said stationary winding.

2. The invention of claim 1 wherein the said windings are spacedadjacent each other in the said air gap between the said cores.

References Cited UNITED STATES PATENTS 2,650,290 8/1953 Newhouse219--10.69 2,681,975 6/1954 Leonard 219-10.69 2,882,378 4/1959 Ticehurst219--10.69 3,187,150 6/1965 France 21910.49

RICHARD M. WOOD, Primary Examiner.

L. H. BENDER, Assistant Examiner.

US. Cl. X.R. 219471

